摘要:

A relatively simple technique employing a two‐dimensional form of the temperature wave method is described. With reasonable care, both the specific heat and the thermal conductivity may be measured with an accuracy of 1% and a precision of 0.1%. Samples as small as 5×7 mm may readily be studied. The region of the sample in which the measurements are made is quite small and may be maintained isothermal to better than 15 mK, making the method suitable for use near phase transitions. The method should also be useful in applied fields and at high pressures or temperatures.

ISSN:0034-6748    

DOI:10.1063/1.1134539

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A 255 picture element imaging device for astronomical applications in theJandKatmospheric windows (1.5‐ to 1.8‐&mgr; and 2.0‐ to 2.4‐&mgr; wavelength, respectively) is described. Spatial information is optically encoded and detected by a LN2‐cooled detector. Electronic decoding is achieved during measurement by means of a special purpose computer. Under seeing and scintillation noise limited conditions a multiplex advantage of a factor of 8 is attained.

ISSN:0034-6748    

DOI:10.1063/1.1134540

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A torsion pendulum device is described for measuring the amplitude‐dependent damping properties of high‐temperature alloys both at room temperature and at elevated temperatures. Its features include the use of data processing techniques for rapid access to damping information and the use of a simple specimen geometry to allow specimens to be cut from bulk engineering samples. Some typical results obtained with the system are given to illustrate its capabilities and the extraneous background losses in the machine are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1134542

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A new modification of the diamond anvil pressure that can achieve up to 300 kilobars and 1000°C is described. The new modification employs a new alignment technique and a new heating element and is aversatile apparatus for research at high pressure and high temperature.

ISSN:0034-6748    

DOI:10.1063/1.1134543

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The LURE synchrotron radiation facility is described. We emphasize the scientific and technological considerations that led to our practical choice of transfer optics, vacuum equipment, and fail safe system based on the use of an acoustical delay line. Characteristics of the vacuum beam lines are given as well as the actual performance of the system as a practical light source.

ISSN:0034-6748    

DOI:10.1063/1.1134544

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Plasma interferometry using the fringe shift technique has been extended to the 100‐MHz range by the use of Bragg diffraction in a lead molybdate acousto‐optic cell. The cell splits a 633‐nm laser beam into zero and first‐order beams, which are separated in frequency by 80 MHz. These beams are used in the scene and reference arms of a modified Michelson interferometer and are then recombined on a silicon photodetector. Phase changes are deduced from the variations in time separation of consecutive peaks in the beat signal. The technique has been used to make electron density measurements in a 1‐m‐long, shock heated theta pinch with 6‐nsec time resolution. Density variations during the implosion produce a total phase shift of nearly 1 fringe in 150 nsec. Phase noise in vacuum shots (without plasma) is 1/40 fringe rms; the peak‐to‐peak noise is 1/10 fringe, thus corresponding to a maximum area density (Fn dl) uncertainty of 2×1016cm−2.

ISSN:0034-6748    

DOI:10.1063/1.1134545

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A position‐sensitive event‐counting electronic readout system for microchannel plates (MCPs) is described that offers the advantages of high spatial resolution and fast time resolution. The technique relies upon a four‐quadrant electron‐collecting anode located behind the output face of the microchannel plate, so that the electron cloud from each detected event is partly intercepted by each of the four quadrants. The relative amounts of charge collected by each quadrant depend on event position, permitting each event to be localized with two ratio circuits. A prototype quadrant anode system for ion, electron, and extreme ultraviolet imaging is described. The spatial resolution achieved, ?10 &mgr;, allows individual MCP channels to be distinguished.

ISSN:0034-6748    

DOI:10.1063/1.1134524

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The cable temperature jump apparatus developed by Hoffman is modified in order to suppress artifacts like electrodichroism and electroluminescence. Construction of a polarization optics with strain‐free quartz windows in the temperature jump cell as well as application of interference–reflection filters allows the elimination of these artifacts. The reconstruction leads to an increase in sensitivity and also to an extension of the time resolution to 10 nsec.

ISSN:0034-6748    

DOI:10.1063/1.1134525

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Development of new semiconductor technologies frequently requires impurity density analysis on material with high leakage currents or deep level contamination. Previously described impurity profilers provide minimal diagnostics for such cases. We have constructed a new variable‐frequency capacitance/conductance analysis system applicable to impurity profile, Schottky barrier height, MOS interface state, and deep level analysis. The system, which consists almost entirely of commercial ’’building blocks,’’ uses phase‐sensitive detection to provide better than 40‐dB isolation between capacitance and conductance signals. For impurity profile measurements a two‐frequency intermodulation technique avoids the stringent filtering requirements inherent in the Copeland plotter. In this mode the system can measure either capacitance,C, anddC/dVor conductance,G, anddG/dVover two decades in frequency. A small‐scale analog computer integral with the unit allows presentation of the data as impurity profiles. A simple change of circuit parameters permits measurements ofCorGwith amplitude response flat within 1% over four decades of frequency. The computer may then be used to present the results in formats appropriate to Schottky barrier height or deep level determinations.

ISSN:0034-6748    

DOI:10.1063/1.1134526

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

An electronic unit for maintaining plate parallelism in a scanning Fabry–Perot is discussed. The unit is a digital version of an analog unit previously described. It offers significantly improved performance over the analog unit, and is capable of maintaining high finesse for many hours under low input light conditions. In a test using high‐reflectance plates in a triple‐passed system, the unit held a finesse of 84 over a period of 7 h with a Rayleigh peak height of 2100 counts/sec.

ISSN:0034-6748    

DOI:10.1063/1.1134527

出版商:AIP    

年代:1976

数据来源: AIP